xdf importer unit tests

[cboulay]

@arnodelorme @chkothe @dmedine @tstenner @cll008 @dojeda @aojeda

Based on our meeting, the next steps forward for XDF are to create unit tests. Don't worry about the platform (Win/Mac/Linux x Matlab/Python) yet. For now, we need sample files and a list of desired unit tests.

Please provide your desired unit tests and offer up problematic data files. We need tests to verify healthy & perfectly formatted files, as well as tests for problematic files (unusual jitter, missing nominal_rate, poorly formatted XML headers, etc.).

[cboulay]

I don't have GitHub usernames for everyone. Please feel free to tag other users.

[dmedine]

This issue seems to be a bit of a stub, but I recently implemented some XDF unit tests for a consulting job and checked that the following cases were correct for each combination of HandleClockSynchronization and HandleJitterRemoval:

-standard xdf with eeg and markers
-data with gaps
-data with clock resets
-data with each possible format type represented as both data and marker stream

Any unit test should also, of course, trigger any and all exceptions/error handling in one way or another.

I'd be happy to share the XDF sample files I used.

[cboulay]

If they are small they can go here: https://github.com/xdf-modules/example-files

There's an outstanding PR to add that as a xdf submodule: #47

I have no idea if that particular submodule is currently being used by any unit tests that are part of any CI.